#include <iostream>
#include <iomanip>
#include <cmath>

using namespace std;

int main() {
    double a, b;
    double ans;
    cin >> a >> b;
    if(a==b)
        ans = sqrt(a * a * 2);
    else {
        if(b > a) {
            double temp = a;
            a = b;
            b = temp;
        }
        ans = sqrt(a*a - b*b);
    }
    cout << fixed << setprecision(6) << ans << endl;
}